Non-overlapping uvs?

[HammerFist132]

I see many people on the internet like more non-overlapping uvs, but what are they and why are they better?

 

[Talavaj]

Overlapping mapping is using the texture on multiple faces. Pretty much all wow/wc3 models use overlapping because models are symmetrical and as such it would be waste of effort and video memory to make similar texture for both sides.
Texture tiling is similar although it is not technically overlapping. (but it has the same drawbacks that the overlapping has)

Advantages of non-overlapping are that you can draw a unique texture on every face but it also requires much more video ram because of the texture dimensions having to be much bigger to fit everything on.
In some cases, non-overlapping is absolutely essential such as in cases of texture baking (such as normal map baking).

In case of wc3 going for non-overlapping wraps is a horrible idea because the texture dimensions are very limited to begin with.
Otherwise, there is not much else non-overlapping is good for, though it is commonly used nowadays, especially on character models because normal maps are a standard nowadays.

You "overlap" by either using multiple unwrap modifiers, creating uv seams in the process that require vertices to be duplicated when rendered which raises the "poly count" or by "folding" the wrap back as is done with symmetrical models.

 

[Kwaliti]

As an example for Talavaj's explanation:

Clicky

Image found via Google Images

This is a very rough example of a non-overlapping texture. The unwrap is basically cylindrical for this texture and no face belonging to the head will get the same area.

You're already familiar with how Arthas' face, for example, is wrapped. That is an overlapping texture.

 

[Kyrbi0]

Quite helpful, but that's day-ung creepy to run into into all of a sudden, Kwaliti. Hidden tags that pic?